THE PTEEOSATJEIA. 



267 



dorsal, sacral, and caudal regions, the cervical vertebrae 

 being, as in Birds, the stoutest of aU, The atlas and axis 



Fig. 79. 



Fig. 79.^ — The nearly entire skeleton of Pterodacti/lus sperfabiUs (Von 

 Meyer) as shown by the two halves of a split block of lithographic 

 slate, a, the left pre-pubic bone: on the right side this bone is 

 not shown and the ilium is e.'iposed. 



are ankylosed together, at least in the cretaceous species. 

 The other cervical vertebrae, apparently not more than six 



